An airbag module is part of an inflatable restraint system employed in a vehicle, especially in an automobile, for protecting an occupant against injury. The module deploys an inflated airbag cushion to physically restrain the occupant's body when the vehicle encounters a collision. The airbag module normally includes an inflatable airbag cushion and an inflator that, once triggered by a remote collision sensor, provides inflation gas for inflating the airbag cushion.
As its name implies, a side airbag module protects an occupant against an impact to the side of the vehicle and is normally positioned somewhere between the occupant and the side of the vehicle closest to the occupant. One option for a side airbag module mounting location which has proven advantageous is in the center or "B" pillar of the auto. This location is advantageous because the airbag module is ideally positioned with respect to a front and a rear passenger. In addition, the center pillar is relatively spacious and provides easy access for the airbag module control wiring.
In order to reduce weight and costs, providing a side airbag module that provides protection for both a front and a rear vehicle occupant would be generally preferable over having to provide a separate side airbag module for each occupant. Providing a single side airbag module for protecting both a front and a rear vehicle occupant, however, would generally mean having a single inflator and a relatively large airbag cushion having a front segment for the front occupant and a rear segment for the rear occupant.
One problem with providing a large side airbag cushion is that inflation gas within the fully inflated airbag cushion may be squeezed or transferred from the front segment to the rear segment, or vice versa, if only one occupant strikes the airbag cushion or if the front and rear occupants strike the airbag cushion at different times. Inflation gas permitted to be squeezed out of a segment of the inflated airbag cushion would cause that segment to collapse and not provide the desired protection to an occupant. Such a large side airbag cushion would therefore have to include means for preventing inflation gas from being squeezed or transferred out of the front and rear segments during or after inflation of the airbag cushion.
A similar problem occurs when a single inflation source is employed to inflate a large frontal airbag having a plurality of inflation chambers for protecting one or more occupants of a motor vehicle or when a single inflation source is utilized to inflate at least two airbags.